NAME

git-rev-parse - Pick out and massage parameters

SYNOPSIS

git rev-parse [<options>] <args>…​

DESCRIPTION

Many Git porcelainish commands take mixture of flags
(i.e. parameters that begin with a dash -) and parameters
meant for the underlying git rev-list command they use internally
and flags and parameters for the other commands they use
downstream of git rev-list. This command is used to
distinguish between them.

Verify that exactly one parameter is provided, and that it
can be turned into a raw 20-byte SHA-1 that can be used to
access the object database. If so, emit it to the standard
output; otherwise, error out.

If you want to make sure that the output actually names an object in
your object database and/or can be used as a specific type of object
you require, you can add the ^{type} peeling operator to the parameter.
For example, git rev-parse "$VAR^{commit}" will make sure $VAR
names an existing object that is a commit-ish (i.e. a commit, or an
annotated tag that points at a commit). To make sure that $VAR
names an existing object of any type, git rev-parse "$VAR^{object}"
can be used.

-q

--quiet

Only meaningful in --verify mode. Do not output an error
message if the first argument is not a valid object name;
instead exit with non-zero status silently.
SHA-1s for valid object names are printed to stdout on success.

--sq

Usually the output is made one line per flag and
parameter. This option makes output a single line,
properly quoted for consumption by shell. Useful when
you expect your parameter to contain whitespaces and
newlines (e.g. when using pickaxe -S with
git diff-*). In contrast to the --sq-quote option,
the command input is still interpreted as usual.

--short[=length]

Same as --verify but shortens the object name to a unique
prefix with at least length characters. The minimum length
is 4, the default is the effective value of the core.abbrev
configuration variable (see git-config[1]).

--not

When showing object names, prefix them with ^ and
strip ^ prefix from the object names that already have
one.

--abbrev-ref[=(strict|loose)]

A non-ambiguous short name of the objects name.
The option core.warnAmbiguousRefs is used to select the strict
abbreviation mode.

--symbolic

Usually the object names are output in SHA-1 form (with
possible ^ prefix); this option makes them output in a
form as close to the original input as possible.

--symbolic-full-name

This is similar to --symbolic, but it omits input that
are not refs (i.e. branch or tag names; or more
explicitly disambiguating "heads/master" form, when you
want to name the "master" branch when there is an
unfortunately named tag "master"), and show them as full
refnames (e.g. "refs/heads/master").

Options for Objects

--all

Show all refs found in refs/.

--branches[=pattern]

--tags[=pattern]

--remotes[=pattern]

Show all branches, tags, or remote-tracking branches,
respectively (i.e., refs found in refs/heads,
refs/tags, or refs/remotes, respectively).

If a pattern is given, only refs matching the given shell glob are
shown. If the pattern does not contain a globbing character (?,
*, or [), it is turned into a prefix match by appending /*.

--glob=pattern

Show all refs matching the shell glob pattern pattern. If
the pattern does not start with refs/, this is automatically
prepended. If the pattern does not contain a globbing
character (?, *, or [), it is turned into a prefix
match by appending /*.

--exclude=<glob-pattern>

Do not include refs matching <glob-pattern> that the next --all,
--branches, --tags, --remotes, or --glob would otherwise
consider. Repetitions of this option accumulate exclusion patterns
up to the next --all, --branches, --tags, --remotes, or
--glob option (other options or arguments do not clear
accumulated patterns).

The patterns given should not begin with refs/heads, refs/tags, or
refs/remotes when applied to --branches, --tags, or --remotes,
respectively, and they must begin with refs/ when applied to --glob
or --all. If a trailing /* is intended, it must be given
explicitly.

--disambiguate=<prefix>

Show every object whose name begins with the given prefix.
The <prefix> must be at least 4 hexadecimal digits long to
avoid listing each and every object in the repository by
mistake.

Options for Files

--local-env-vars

List the GIT_* environment variables that are local to the
repository (e.g. GIT_DIR or GIT_WORK_TREE, but not GIT_EDITOR).
Only the names of the variables are listed, not their value,
even if they are set.

--git-dir

Show $GIT_DIR if defined. Otherwise show the path to
the .git directory. The path shown, when relative, is
relative to the current working directory.

If $GIT_DIR is not defined and the current directory
is not detected to lie in a Git repository or work tree
print a message to stderr and exit with nonzero status.

--absolute-git-dir

Like --git-dir, but its output is always the canonicalized
absolute path.

--git-common-dir

Show $GIT_COMMON_DIR if defined, else $GIT_DIR.

--is-inside-git-dir

When the current working directory is below the repository
directory print "true", otherwise "false".

--is-inside-work-tree

When the current working directory is inside the work tree of the
repository print "true", otherwise "false".

--is-bare-repository

When the repository is bare print "true", otherwise "false".

--is-shallow-repository

When the repository is shallow print "true", otherwise "false".

--resolve-git-dir <path>

Check if <path> is a valid repository or a gitfile that
points at a valid repository, and print the location of the
repository. If <path> is a gitfile then the resolved path
to the real repository is printed.

--git-path <path>

Resolve "$GIT_DIR/<path>" and takes other path relocation
variables such as $GIT_OBJECT_DIRECTORY,
$GIT_INDEX_FILE…​ into account. For example, if
$GIT_OBJECT_DIRECTORY is set to /foo/bar then "git rev-parse
--git-path objects/abc" returns /foo/bar/abc.

--show-cdup

When the command is invoked from a subdirectory, show the
path of the top-level directory relative to the current
directory (typically a sequence of "../", or an empty string).

--show-prefix

When the command is invoked from a subdirectory, show the
path of the current directory relative to the top-level
directory.

--show-toplevel

Show the absolute path of the top-level directory.

--show-superproject-working-tree

Show the absolute path of the root of the superproject’s
working tree (if exists) that uses the current repository as
its submodule. Outputs nothing if the current repository is
not used as a submodule by any project.

--shared-index-path

Show the path to the shared index file in split index mode, or
empty if not in split-index mode.

Other Options

--since=datestring

--after=datestring

Parse the date string, and output the corresponding
--max-age= parameter for git rev-list.

--until=datestring

--before=datestring

Parse the date string, and output the corresponding
--min-age= parameter for git rev-list.

<args>…​

Flags and parameters to be parsed.

SPECIFYING REVISIONS

A revision parameter <rev> typically, but not necessarily, names a
commit object. It uses what is called an extended SHA-1
syntax. Here are various ways to spell object names. The
ones listed near the end of this list name trees and
blobs contained in a commit.

Note

This document shows the "raw" syntax as seen by git. The shell
and other UIs might require additional quoting to protect special
characters and to avoid word splitting.

<sha1>, e.g. dae86e1950b1277e545cee180551750029cfe735, dae86e

The full SHA-1 object name (40-byte hexadecimal string), or
a leading substring that is unique within the repository.
E.g. dae86e1950b1277e545cee180551750029cfe735 and dae86e both
name the same commit object if there is no other object in
your repository whose object name starts with dae86e.

<describeOutput>, e.g. v1.7.4.2-679-g3bee7fb

Output from git describe; i.e. a closest tag, optionally
followed by a dash and a number of commits, followed by a dash, a
g, and an abbreviated object name.

<refname>, e.g. master, heads/master, refs/heads/master

A symbolic ref name. E.g. master typically means the commit
object referenced by refs/heads/master. If you
happen to have both heads/master and tags/master, you can
explicitly say heads/master to tell Git which one you mean.
When ambiguous, a <refname> is disambiguated by taking the
first match in the following rules:

If $GIT_DIR/<refname> exists, that is what you mean (this is usually
useful only for HEAD, FETCH_HEAD, ORIG_HEAD, MERGE_HEAD
and CHERRY_PICK_HEAD);

otherwise, refs/<refname> if it exists;

otherwise, refs/tags/<refname> if it exists;

otherwise, refs/heads/<refname> if it exists;

otherwise, refs/remotes/<refname> if it exists;

otherwise, refs/remotes/<refname>/HEAD if it exists.

HEAD names the commit on which you based the changes in the working tree.
FETCH_HEAD records the branch which you fetched from a remote repository
with your last git fetch invocation.
ORIG_HEAD is created by commands that move your HEAD in a drastic
way, to record the position of the HEAD before their operation, so that
you can easily change the tip of the branch back to the state before you ran
them.
MERGE_HEAD records the commit(s) which you are merging into your branch
when you run git merge.
CHERRY_PICK_HEAD records the commit which you are cherry-picking
when you run git cherry-pick.

Note that any of the refs/* cases above may come either from
the $GIT_DIR/refs directory or from the $GIT_DIR/packed-refs file.
While the ref name encoding is unspecified, UTF-8 is preferred as
some output processing may assume ref names in UTF-8.

@

@ alone is a shortcut for HEAD.

<refname>@{<date>}, e.g. master@{yesterday}, HEAD@{5 minutes ago}

A ref followed by the suffix @ with a date specification
enclosed in a brace
pair (e.g. {yesterday}, {1 month 2 weeks 3 days 1 hour 1
second ago} or {1979-02-26 18:30:00}) specifies the value
of the ref at a prior point in time. This suffix may only be
used immediately following a ref name and the ref must have an
existing log ($GIT_DIR/logs/<ref>). Note that this looks up the state
of your local ref at a given time; e.g., what was in your local
master branch last week. If you want to look at commits made during
certain times, see --since and --until.

<refname>@{<n>}, e.g. master@{1}

A ref followed by the suffix @ with an ordinal specification
enclosed in a brace pair (e.g. {1}, {15}) specifies
the n-th prior value of that ref. For example master@{1}
is the immediate prior value of master while master@{5}
is the 5th prior value of master. This suffix may only be used
immediately following a ref name and the ref must have an existing
log ($GIT_DIR/logs/<refname>).

@{<n>}, e.g. @{1}

You can use the @ construct with an empty ref part to get at a
reflog entry of the current branch. For example, if you are on
branch blabla then @{1} means the same as blabla@{1}.

@{-<n>}, e.g. @{-1}

The construct @{-<n>} means the <n>th branch/commit checked out
before the current one.

<branchname>@{upstream}, e.g. master@{upstream}, @{u}

The suffix @{upstream} to a branchname (short form <branchname>@{u})
refers to the branch that the branch specified by branchname is set to build on
top of (configured with branch.<name>.remote and
branch.<name>.merge). A missing branchname defaults to the
current one. These suffixes are also accepted when spelled in uppercase, and
they mean the same thing no matter the case.

<branchname>@{push}, e.g. master@{push}, @{push}

The suffix @{push} reports the branch "where we would push to" if
git push were run while branchname was checked out (or the current
HEAD if no branchname is specified). Since our push destination is
in a remote repository, of course, we report the local tracking branch
that corresponds to that branch (i.e., something in refs/remotes/).

Note in the example that we set up a triangular workflow, where we pull
from one location and push to another. In a non-triangular workflow,
@{push} is the same as @{upstream}, and there is no need for it.

This suffix is also accepted when spelled in uppercase, and means the same
thing no matter the case.

<rev>^, e.g. HEAD^, v1.5.1^0

A suffix ^ to a revision parameter means the first parent of
that commit object. ^<n> means the <n>th parent (i.e.
<rev>^
is equivalent to <rev>^1). As a special rule,
<rev>^0 means the commit itself and is used when <rev> is the
object name of a tag object that refers to a commit object.

<rev>~<n>, e.g. master~3

A suffix ~<n> to a revision parameter means the commit
object that is the <n>th generation ancestor of the named
commit object, following only the first parents. I.e. <rev>~3 is
equivalent to <rev>^^^ which is equivalent to
<rev>^1^1^1. See below for an illustration of
the usage of this form.

<rev>^{<type>}, e.g. v0.99.8^{commit}

A suffix ^ followed by an object type name enclosed in
brace pair means dereference the object at <rev> recursively until
an object of type <type> is found or the object cannot be
dereferenced anymore (in which case, barf).
For example, if <rev> is a commit-ish, <rev>^{commit}
describes the corresponding commit object.
Similarly, if <rev> is a tree-ish, <rev>^{tree}
describes the corresponding tree object.
<rev>^0
is a short-hand for <rev>^{commit}.

rev^{object} can be used to make sure rev names an
object that exists, without requiring rev to be a tag, and
without dereferencing rev; because a tag is already an object,
it does not have to be dereferenced even once to get to an object.

rev^{tag} can be used to ensure that rev identifies an
existing tag object.

<rev>^{}, e.g. v0.99.8^{}

A suffix ^ followed by an empty brace pair
means the object could be a tag,
and dereference the tag recursively until a non-tag object is
found.

<rev>^{/<text>}, e.g. HEAD^{/fix nasty bug}

A suffix ^ to a revision parameter, followed by a brace
pair that contains a text led by a slash,
is the same as the :/fix nasty bug syntax below except that
it returns the youngest matching commit which is reachable from
the <rev> before ^.

:/<text>, e.g. :/fix nasty bug

A colon, followed by a slash, followed by a text, names
a commit whose commit message matches the specified regular expression.
This name returns the youngest matching commit which is
reachable from any ref, including HEAD.
The regular expression can match any part of the
commit message. To match messages starting with a string, one can use
e.g. :/^foo. The special sequence :/! is reserved for modifiers to what
is matched. :/!-foo performs a negative match, while :/!!foo matches a
literal ! character, followed by foo. Any other sequence beginning with
:/! is reserved for now.
Depending on the given text, the shell’s word splitting rules might
require additional quoting.

<rev>:<path>, e.g. HEAD:README, :README, master:./README

A suffix : followed by a path names the blob or tree
at the given path in the tree-ish object named by the part
before the colon.
:path (with an empty part before the colon)
is a special case of the syntax described next: content
recorded in the index at the given path.
A path starting with ./ or ../ is relative to the current working directory.
The given path will be converted to be relative to the working tree’s root directory.
This is most useful to address a blob or tree from a commit or tree that has
the same tree structure as the working tree.

:<n>:<path>, e.g. :0:README, :README

A colon, optionally followed by a stage number (0 to 3) and a
colon, followed by a path, names a blob object in the
index at the given path. A missing stage number (and the colon
that follows it) names a stage 0 entry. During a merge, stage
1 is the common ancestor, stage 2 is the target branch’s version
(typically the current branch), and stage 3 is the version from
the branch which is being merged.

Here is an illustration, by Jon Loeliger. Both commit nodes B
and C are parents of commit node A. Parent commits are ordered
left-to-right.

SPECIFYING RANGES

History traversing commands such as git log operate on a set
of commits, not just a single commit.

For these commands,
specifying a single revision, using the notation described in the
previous section, means the set of commits reachable from the given
commit.

A commit’s reachable set is the commit itself and the commits in
its ancestry chain.

Commit Exclusions

^<rev> (caret) Notation

To exclude commits reachable from a commit, a prefix ^
notation is used. E.g. ^r1 r2 means commits reachable
from r2 but exclude the ones reachable from r1 (i.e. r1 and
its ancestors).

Dotted Range Notations

The .. (two-dot) Range Notation

The ^r1 r2 set operation appears so often that there is a shorthand
for it. When you have two commits r1 and r2 (named according
to the syntax explained in SPECIFYING REVISIONS above), you can ask
for commits that are reachable from r2 excluding those that are reachable
from r1 by ^r1 r2 and it can be written as r1..r2.

The …​ (three-dot) Symmetric Difference Notation

A similar notation r1...r2 is called symmetric difference
of r1 and r2 and is defined as
r1 r2 --not $(git merge-base --all r1 r2).
It is the set of commits that are reachable from either one of
r1 (left side) or r2 (right side) but not from both.

In these two shorthand notations, you can omit one end and let it default to HEAD.
For example, origin.. is a shorthand for origin..HEAD and asks "What
did I do since I forked from the origin branch?" Similarly, ..origin
is a shorthand for HEAD..origin and asks "What did the origin do since
I forked from them?" Note that .. would mean HEAD..HEAD which is an
empty range that is both reachable and unreachable from HEAD.

Other <rev>^ Parent Shorthand Notations

Three other shorthands exist, particularly useful for merge commits,
for naming a set that is formed by a commit and its parent commits.

The r1^@ notation means all parents of r1.

The r1^! notation includes commit r1 but excludes all of its parents.
By itself, this notation denotes the single commit r1.

The <rev>^-<n> notation includes <rev> but excludes the <n>th
parent (i.e. a shorthand for <rev>^<n>..<rev>), with <n> = 1 if
not given. This is typically useful for merge commits where you
can just pass <commit>^- to get all the commits in the branch
that was merged in merge commit <commit> (including <commit>
itself).

While <rev>^<n> was about specifying a single commit parent, these
three notations also consider its parents. For example you can say
HEAD^2^@, however you cannot say HEAD^@^2.

Revision Range Summary

<rev>

Include commits that are reachable from <rev> (i.e. <rev> and its
ancestors).

^<rev>

Exclude commits that are reachable from <rev> (i.e. <rev> and its
ancestors).

<rev1>..<rev2>

Include commits that are reachable from <rev2> but exclude
those that are reachable from <rev1>. When either <rev1> or
<rev2> is omitted, it defaults to HEAD.

<rev1>...<rev2>

Include commits that are reachable from either <rev1> or
<rev2> but exclude those that are reachable from both. When
either <rev1> or <rev2> is omitted, it defaults to HEAD.

<rev>^@, e.g. HEAD^@

A suffix ^ followed by an at sign is the same as listing
all parents of <rev> (meaning, include anything reachable from
its parents, but not the commit itself).

<rev>^!, e.g. HEAD^!

A suffix ^ followed by an exclamation mark is the same
as giving commit <rev> and then all its parents prefixed with
^ to exclude them (and their ancestors).

<rev>^-<n>, e.g. HEAD^-, HEAD^-2

Equivalent to <rev>^<n>..<rev>, with <n> = 1 if not
given.

Here are a handful of examples using the Loeliger illustration above,
with each step in the notation’s expansion and selection carefully
spelt out:

PARSEOPT

In --parseopt mode, git rev-parse helps massaging options to bring to shell
scripts the same facilities C builtins have. It works as an option normalizer
(e.g. splits single switches aggregate values), a bit like getopt(1) does.

It takes on the standard input the specification of the options to parse and
understand, and echoes on the standard output a string suitable for sh(1)eval
to replace the arguments with normalized ones. In case of error, it outputs
usage on the standard error stream, and exits with code 129.

Note: Make sure you quote the result when passing it to eval. See
below for an example.

Input Format

git rev-parse --parseopt input format is fully text based. It has two parts,
separated by a line that contains only --. The lines before the separator
(should be one or more) are used for the usage.
The lines after the separator describe the options.

Each line of options has this format:

<opt-spec><flags>*<arg-hint>? SP+ help LF

<opt-spec>

its format is the short option character, then the long option name
separated by a comma. Both parts are not required, though at least one
is necessary. May not contain any of the <flags> characters.
h,help, dry-run and f are examples of correct <opt-spec>.

<flags>

<flags> are of *, =, ? or !.

Use = if the option takes an argument.

Use ? to mean that the option takes an optional argument. You
probably want to use the --stuck-long mode to be able to
unambiguously parse the optional argument.

Use * to mean that this option should not be listed in the usage
generated for the -h argument. It’s shown for --help-all as
documented in gitcli[7].

Use ! to not make the corresponding negated long option available.

<arg-hint>

<arg-hint>, if specified, is used as a name of the argument in the
help output, for options that take arguments. <arg-hint> is
terminated by the first whitespace. It is customary to use a
dash to separate words in a multi-word argument hint.

The remainder of the line, after stripping the spaces, is used
as the help associated to the option.

Blank lines are ignored, and lines that don’t match this specification are used
as option group headers (start the line with a space to create such
lines on purpose).

Example

OPTS_SPEC="\
some-command [<options>] <args>...
some-command does foo and bar!
--
h,help show the help
foo some nifty option --foo
bar= some cool option --bar with an argument
baz=arg another cool option --baz with a named argument
qux?path qux may take a path argument but has meaning by itself
An option group Header
C? option C with an optional argument"
eval "$(echo "$OPTS_SPEC" | git rev-parse --parseopt -- "$@" || echo exit $?)"

Usage text

When "$@" is -h or --help in the above example, the following
usage text would be shown:

usage: some-command [<options>] <args>...
some-command does foo and bar!
-h, --help show the help
--foo some nifty option --foo
--bar ... some cool option --bar with an argument
--baz <arg> another cool option --baz with a named argument
--qux[=<path>] qux may take a path argument but has meaning by itself
An option group Header
-C[...] option C with an optional argument

SQ-QUOTE

In --sq-quote mode, git rev-parse echoes on the standard output a
single line suitable for sh(1)eval. This line is made by
normalizing the arguments following --sq-quote. Nothing other than
quoting the arguments is done.

If you want command input to still be interpreted as usual by
git rev-parse before the output is shell quoted, see the --sq
option.